Abstract: A group of transistors is configured to drive a bus at time slots, to express data on the bus. The group of transistors dissipates an amount of electrical energy when driving the bus to a logic level opposite to a logic level present on the bus in an immediate preceding time slot. The group of transistors is arranged to dump another amount of electrical energy. Dumping of the other amount of electrical energy is responsive to driving the bus to a logic level that is the same as present on the bus in an immediate preceding time slot. The dumped amount of electrical energy is equivalent to the amount of energy dissipated by the transistors when transitioning the bus to a different logic level. Other aspects are also described.

Abstract: A hearable has an audio amplifier circuit coupled to a speaker as a load. The amplifier circuit has current source drive, which attenuates electromagnetically coupled noise of the speaker. In other instances, the amplifier circuit has a first amplifier mode and a second amplifier mode, wherein in the first amplifier mode the amplifier circuit becomes configured to drive the speaker as a voltage source, and in the second amplifier mode the amplifier circuit becomes configured to drive the speaker as a current source. Control logic varies the amplifier circuit between i) the first amplifier mode for larger amplitudes of the audio signal, and ii) the second amplifier mode for smaller amplitudes of the audio signal. Other aspects are also described and claimed.

Abstract: A group of transistors is configured to drive a bus at time slots, to express data on the bus. The group of transistors dissipates an amount of electrical energy when driving the bus to a logic level opposite to a logic level present on the bus in an immediate preceding time slot. The group of transistors is arranged to dump another amount of electrical energy. Dumping of the other amount of electrical energy is responsive to driving the bus to a logic level that is the same as present on the bus in an immediate preceding time slot. The dumped amount of electrical energy is equivalent to the amount of energy dissipated by the transistors when transitioning the bus to a different logic level. Other aspects are also described.

Abstract: A group of transistors is configured to drive a bus at time slots, to express data on the bus. The group of transistors dissipates an amount of electrical energy when driving the bus to a logic level opposite to a logic level present on the bus in an immediate preceding time slot. The group of transistors is arranged to dump another amount of electrical energy. Dumping of the other amount of electrical energy is responsive to driving the bus to a logic level that is the same as present on the bus in an immediate preceding time slot. The dumped amount of electrical energy is equivalent to the amount of energy dissipated by the transistors when transitioning the bus to a different logic level. Other aspects are also described.

Abstract: A power converter produces power at a greater voltage than provided by a power source, while drawing power from the power source, wherein the power converter has a variable input current limit or a variable input power limit. One or more audio amplifiers are configured into i) drawing power from the power source bypassing the power converter and ii) drawing power from the power converter, according to audio signal amplitude, during audio playback and in accordance with an audio signal being amplified. A load of each amplifier is determined for when the amplifier is drawing power from the power source bypassing the power converter. The variable input limit of the power converter is adjusted in accordance with the determined load, during the audio playback. Other aspects are also described and claimed.

Abstract: An audio amplifier has an analog current source amplifier and a class D amplifier. The analog current source amplifier is active in a first mode to drive a speaker when an audio signal has smaller amplitude. The class D amplifier is active in a second mode to drive the speaker when the audio signal has larger amplitude. Other aspects are also described and claimed.

Abstract: A hearable has an audio amplifier circuit coupled to a speaker as a load. The amplifier circuit has current source drive, which attenuates electromagnetically coupled noise of the speaker. In other instances, the amplifier circuit has a first amplifier mode and a second amplifier mode, wherein in the first amplifier mode the amplifier circuit becomes configured to drive the speaker as a voltage source, and in the second amplifier mode the amplifier circuit becomes configured to drive the speaker as a current source. Control logic varies the amplifier circuit between i) the first amplifier mode for larger amplitudes of the audio signal, and ii) the second amplifier mode for smaller amplitudes of the audio signal. Other aspects are also described and claimed.

Abstract: A hearable has an audio amplifier circuit coupled to a speaker as a load. The amplifier circuit has current source drive, which attenuates electromagnetically coupled noise of the speaker. In other instances, the amplifier circuit has a first amplifier mode and a second amplifier mode, wherein in the first amplifier mode the amplifier circuit becomes configured to drive the speaker as a voltage source, and in the second amplifier mode the amplifier circuit becomes configured to drive the speaker as a current source. Control logic varies the amplifier circuit between i) the first amplifier mode for larger amplitudes of the audio signal, and ii) the second amplifier mode for smaller amplitudes of the audio signal. Other aspects are also described and claimed.

Abstract: An audio amplifier has a first H bridge and a second H bridge, to drive a speaker as a load. The second H bridge drives the speaker through resistors for increased output impedance. Control logic operates the first H bridge as a class D amplifier for larger amplitudes of audio signal, and operates the second H bridge as a class D amplifier for smaller amplitudes of audio signal. Other aspects are also described and claimed.

Abstract: A hearable has an audio amplifier circuit coupled to a speaker as a load. The amplifier circuit has current source drive, which attenuates electromagnetically coupled noise of the speaker. In other instances, the amplifier circuit has a first amplifier mode and a second amplifier mode, wherein in the first amplifier mode the amplifier circuit becomes configured to drive the speaker as a voltage source, and in the second amplifier mode the amplifier circuit becomes configured to drive the speaker as a current source. Control logic varies the amplifier circuit between i) the first amplifier mode for larger amplitudes of the audio signal, and ii) the second amplifier mode for smaller amplitudes of the audio signal. Other aspects are also described and claimed.

Abstract: An audio amplifier has an analog current source amplifier and a class D amplifier. The analog current source amplifier is active in a first mode to drive a speaker when an audio signal has smaller amplitude. The class D amplifier is active in a second mode to drive the speaker when the audio signal has larger amplitude. Other aspects are also described and claimed.

Abstract: An audio amplifier has a first H bridge and a second H bridge, to drive a speaker as a load. The second H bridge drives the speaker through resistors for increased output impedance. Control logic operates the first H bridge as a class D amplifier for larger amplitudes of audio signal, and operates the second H bridge as a class D amplifier for smaller amplitudes of audio signal. Other aspects are also described and claimed.

Abstract: A power converter produces power at a greater voltage than provided by a power source, while drawing power from the power source, wherein the power converter has a variable input current limit or a variable input power limit. One or more audio amplifiers are configured into i) drawing power from the power source bypassing the power converter and ii) drawing power from the power converter, according to audio signal amplitude, during audio playback and in accordance with an audio signal being amplified. A load of each amplifier is determined for when the amplifier is drawing power from the power source bypassing the power converter. The variable input limit of the power converter is adjusted in accordance with the determined load, during the audio playback. Other aspects are also described and claimed.

Abstract: A group of transistors is configured to drive a bus at time slots, to express data on the bus. The group of transistors dissipates an amount of electrical energy when driving the bus to a logic level opposite to a logic level present on the bus in an immediate preceding time slot. The group of transistors is arranged to dump another amount of electrical energy. Dumping of the other amount of electrical energy is responsive to driving the bus to a logic level that is the same as present on the bus in an immediate preceding time slot. The dumped amount of electrical energy is equivalent to the amount of energy dissipated by the transistors when transitioning the bus to a different logic level. Other aspects are also described.

Abstract: A power converter provides a first output voltage and a second output voltage in accordance with a control input, wherein the first output voltage is higher than the second output voltage. A switch that is series coupled between i) an energy reservoir node and ii) a power supply node or a power return node. A charge maintenance circuit is coupled to the energy reservoir node, and when the switch is closed can maintain a selected amount of charge in or a selected voltage across an energy reservoir element that may be coupled to the energy reservoir node. Other aspects are also described and claimed.

Abstract: An excitation signal is produced on a plate of an unknown capacitor and on a plate of a known capacitor. The excitation signal is amplified over time to produce a first output signal, with gain that is proportional to capacitance of the unknown capacitor. The excitation signal is also amplified over time to produce a second output signal, with gain that is proportional to capacitance of the known capacitor. Capacitance of the unknown capacitor is computed using a mathematical function of the first and second output signals and the capacitance of the known capacitor, while being insensitive to amplitude of the excitation signal. Other embodiments are also described and claimed.

Abstract: An analog to digital conversion circuit receives a transducer output signal and outputs a data bitstream, where a latch or flip flop has an input that receives a clock signal. An AC-DC power converter receives the clock signal and produces a DC voltage which may power the analog to digital conversion circuit. The AC-DC power converter has a rectifier, an energy store and a voltage regulator, charge pump or filter, which draws power from the energy store to produce the DC voltage. A control circuit delays replenishment of the energy store by the rectified clock signal, responsive to the clock signal. Other embodiments are also described and claimed.

Abstract: A speaker assembly including a sound radiating surface suspended over a magnet assembly, a suspension member for suspending the sound radiating surface over the magnet assembly, a voice coil extending from a bottom side of the sound radiating surface, and a capacitive displacement sensor for sensing a movement of the sound radiating surface. The capacitive displacement sensor including a first conductive plate fixedly positioned over the sound radiating surface and a second conductive plate coupled to the sound radiating surface and vertically aligned with the first conductive plate, and wherein the second conductive plate is confined to an area that is entirely radially inward of the voice coil.

Abstract: An analog to digital conversion circuit receives a transducer output signal and outputs a data bitstream, where a latch or flip flop has an input that receives a clock signal. An AC-DC power converter receives the clock signal and produces a DC voltage which may power the analog to digital conversion circuit. The AC-DC power converter has a rectifier, an energy store and a voltage regulator, charge pump or filter, which draws power from the energy store to produce the DC voltage. A control circuit delays replenishment of the energy store by the rectified clock signal, responsive to the clock signal. Other embodiments are also described and claimed.

Abstract: A speaker assembly including a sound radiating surface suspended over a magnet assembly, a suspension member for suspending the sound radiating surface over the magnet assembly, a voice coil extending from a bottom side of the sound radiating surface, and a capacitive displacement sensor for sensing a movement of the sound radiating surface. The capacitive displacement sensor including a first conductive plate fixedly positioned over the sound radiating surface and a second conductive plate coupled to the sound radiating surface and vertically aligned with the first conductive plate, and wherein the second conductive plate is confined to an area that is entirely radially inward of the voice coil.